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Centro de Astrofísica da Universidade do Porto

Periodicities in delta Scuti frequency spectra along the HR diagram

A. García Hernández, J. Pascual-Granado, A. Grigahcène, A. Moya Bedón, S. Martín-Ruiz, J. Gutiérrez-Soto, J.-C. Suárez, R. Garrido

Abstract.
Delta Scuti pulsating stars are challenging but interesting targets. They constitute good laboratories for stellar physics theories (such as convection) mainly for the complexity of their structure as reflected in their complex frequency spectra. Any classical asteroseismic study of these stars by individual frequency fitting does not give accurate results and the analysis is not too much useful. Hence, more observables are needed to help in their study.
Some authors have claimed to find periodicities in the frequency spectra of a couple of stars observed from the ground (FG-Vir, Breger et al. 1999; CD-24 7599, Handler et al. 1997). Using CoRoT observations, we have definitely confirmed the presence of such regularities in the frequency spectra of HD 174936 (García Hernández et al 2009) and HD 174966 (presented at the 2nd CoRoT symposium). However, the first question to be addressed at this level is: are these stars peculiar cases? The large sample of delta Scuti stars observed by Kepler offers us the possibility of carrying out an statistical analysis and of studying the behaviour of such structure along the HR diagram. In this talk, we will present the very preliminary results of our work.

20th Stellar Pulsation Conference Series
Granada, Spain
September 2011

Type: Oral comunication

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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